1. Field of the Invention
The present invention relates to a process for the formation of an ignitable mixture from liquid fuel and combustion air, wherein preheated combustion air is conducted within a flow chamber along a surface which is moistened with fuel for take-up of fuel, as well as to an arrangement for the implementation of the process.
2. Discussion of the Prior Art
The formation of ignitable mixtures through the vaporization of fuel in preheated combustion air which is conveyed over a surface moistened by fuel is known in burners, wherein liquid fuel passes through the porous walls of a fuel chamber which is arranged in a flow chamber traversed by preheated combustion air. The fuel vaporized from the porous walls of the fuel chamber into the preheated combustion air so as to form an ignitable fuel-air mixture which is introduceable into a combustion zone in which it can be ignited and combusted. Reference may be had, in this connection, to German patent applications Nos. P 29 12 519.7-13, P 30 13 428.2-13, and P 30 47 702.2. Burners of this type are destined for utilization in industrial furnaces as well as for smaller sized heat generators.
In order to attain the most efficient formation of the ignitable mixture and a complete residue-free combustion, there is required an extremely precisely metered fuel dosage. In the previously mentioned burners this is attempted by adjustment of the oil pressure in the fuel chamber. The oil pressure is so regulated, that the fuel quantity which passes through the porous walls of the fuel chamber is completely taken up by the combustion air flowing within the flow chamber. At an excessively high fuel infeed it is possible that fuel droplets can be pulled along by the combustion air so as to cause an incomplete combustion, which leads to fuel losses and also to environmental contamination. Also disadvantageous is an infeed of fuel into the flow chamber which is too low. The preheated combustion air, in essence, then heats the porous walls of the fuel chamber so as to present the danger that the fuel will crack on the surface moistened by the fuel and form residues which will prevent the further inlet of fuel through the porous walls. Consequently, there is required an extremely sensitive regulation of the burner which will react to changing conditions with only minor delay.